The invention disclosed herein pertains to a scale that displays recipe ingredients or other materials placed on its pan in terms of their volume and it also functions conventionally to display the weight of any substance in terms of metric or English units of measurement. Conceptually, the invention may be considered to be a volumetric-to-gravimetric-to-volumetric converter in one mode and a volumetric-to-gravimetric converter in another mode.
Most food recipes published in the United States express ingredients in volumetric terms such as cups or fractions of a cup, tablespoons or teaspoons and fractions of tablespoons and teaspoons. Measuring ingredients in terms of volume is often inaccurate and can result in baked or cooked products sometimes tasting, looking or feeling different from one production of the recipe to another. A cake, for example, can be considered a failure if it rises too much or simply flops flat like a pancake as a result of too much or too little of an ingredient. Cooks and bakers who may have performed a particular recipe many times, supposedly measuring the same amounts of the ingredients, can be mystified by the fact that on some occasions the result of the recipe is pleasing and on other occasions it is disappointing. A volumetric-to-gravimetric-to volumetric converter can solve the problem.
A study has revealed that variations in the quality of baked and cooked products in the home results primarily from inaccurate measurements of the ingredients of the recipe. The person doing the cooking or baking is not necessarily to blame. The problem results from recipes specifying ingredients in terms of volume instead of, more accurately, in terms of weight. For example, a recipe may call for a cup of an ingredient which is traditionally available in granular form. The cook or baker happens to be using a powdered form of the ingredient. The weight of the same materials can be different for identical volumes because the packing factors can be different which results from there being larger voids in a cup of the coarser material. So, on one occasion, the recipe may get too much of an ingredient when it is in one physical form and on other occasions, too little of the ingredient when it is in another physical form. This is true of materials such as brown sugar, which may be lumpy at one time and finely divided at other times. Flour from different sources can have significant packing density variations. This is true of many finely divided materials as well as granular materials.
Data published by the United States Department of Agriculture reveal substantial variations in the weight, and hence, the quantity of the ingredient in a given volume recited in the recipe. The data are presented in "Average Weight of a Measured Cup of Various Foods", Agricultural Research Service of the U.S. Department of Agriculture, Home Economics Research Report No. 41 which is now out of print but is on U.S. Government Printing Orrice bookstore records. Large variations in weight and, hence, quantity may result simply from the way in which an ingredient is prepared such as whether it is canned, frozen, bottled or dehydrated. Measuring an ingredient in different ways such as by dipping or spooning can cause variations. The inference to be drawn from the foregoing is that higher accuracy and better results in cooking and baking may be obtained by adding ingredients gravimetrically, that is, in terms of their weights rather than volumetrically, or in terms of their volume. Up to the time the invention disclosed herein was made, there has been no volumetric-to-gravimetric converter type of scale device available nor has there been a volumetric-to-gravimetric-to-volumetric converter type of scale available that would afford a cook or baker an opportunity to add ingredients to a recipe mixture where the recipe calls for specified volumes of the ingredients and where the scale would weigh the ingredient and display its amount in terms of volume rather than in terms of weight as conventional scales do or wherein the cook or baker can enter into the scale the volume of an ingredient called for in a recipe or formula and have the scale convert the volume to weight and then display the volume value that was entered originally.
Errors can also be made in measuring quantities of liquid ingredients listed in a recipe. A measuring cup is often held in one hand by the cook or baker while a liquid ingredient is being poured into the cup. The cup may be raised to eye level to see if the level of the liquid is up to the proper graduation mark on the cup. If the cup is not level, a substantial error can result from the liquid being level and the cup being angulated. Even if the cup is placed on a flat surface, as it should for measuring a liquid, there can be an error due to the top edge of the meniscus being higher than the overall level of the liquid. Since the meniscus remains constant for any level of the same liquid in a measuring cup or other measuring instrument, the percentage error becomes greater and greater as the quantity of the liquid being measured becomes smaller.
Other errors in adding solid and liquid ingredients to a recipe mixture can result from not clearing out all of the ingredient from the volume measuring device. For example, if a substance such as honey is measured in a tablespoon or measuring cup, some of it may adhere to the measuring device when it is poured into a recipe mixing bowl. The error can be enlarged by using the same measuring device for the next ingredient to be added, in which case some of the former ingredient might take the place of some of the present ingredient. The latter error can, of course, be avoided if the cook or baker interrupts progress of the recipe to wash and dry the measuring device or devices between using it or them for successive ingredients. An alternative solution is to keep several of each type of measuring device on hand so the devices can be used alternatively and finally cleaned up after the recipe is complete. Neither solution is satisfactory.